Stretching devices for therapy and injury prevention have become important tools for the injured and for athletes. Many of these devices target key muscles or muscle groups, such as the muscle groups of the back of the calf or the thigh. Some of these devices are quite complicated or bulky. For example, U.S. Pat. No. 4,693,470 to Ogawa teaches a stretching device having an angled standing surface that a user stands on to stretch their Achilles' tendons and calves. By varying the angle of the standing surface relative to the ground a user can adjust the degree of stretch created when standing on the device. However, adjusting the angle appears to require stepping off of the device, manipulating the device to achieve a new angle, and stepping back on the device. Accordingly, a user cannot easily increase the stretch during use as muscles and tendons become looser. In addition, the device is bulky, which reduces it portability.
U.S. Pat. No. 6,110,078 to Dyer teaches a passive stretching device for plantar fascia. The device has two hinged plates with a variable tensioning mechanism. A user secures their foot and lower leg to the device and the distal ends of the opposed plates are pulled together with a spring. As with the '470 device to Ogawa, this device is bulky and is not amenable to quick changes in the force applied to the stretching as the muscles become looser. U.S. Pat. No. 5,853,354 (“the '354 patent”) to Kubota teaches a similar device. The device of the '354 patent includes a part that straps to the lower leg of a user and a footplate, with the two parts connected by a hinge. Force is applied by the user to pull the footplate towards the user resulting in dorsiflexion of the user's foot. Again, this is a bulky device and must be strapped to the user's foot and lower leg prior to use.
Other, more simple, devices exist to aid in stretching. For example, U.S. Patent Application Publication No. 2012/0040808 A1 (“Pub. No. '808”) to Khademi describes a stretching and exercise device with a plurality of strap members, including strap members designed to hold a user's foot and a strap member designed to be grasped by a user. Pub. No. '808 describes the device as a “stretching and exercise device adapted for lower body muscle stretch, including the user's lower back and legs” or alternatively, “a stretching and exercise device adapted for isolating and exercising the foot/calf or hamstring/hip muscles of an individual in an efficient and effective manner.” This device employs a complicated system of straps and a plate to stretch the lower calf muscles, and is only capable stretching a single leg at a time.
A number of devices employ multiple straps and/or handles to allow a user to stretch a single leg. For example, U.S. Pat. No. 4,456,249 (“the '249 patent”) to Calabrese teaches a stretching apparatus with two ropes extending from a collar fitting over the head or neck of a user to a foot-receiving stirrup. The ropes have separate handgrips. A user puts one foot in the stirrup and pulls the handgrips to stretch various muscles and tendons while the device is anchored around the head or neck of a user. U.S. Pat. No. 5,518,486 (“the '486 patent”) to Sheeler teaches an exercise device for a variety of exercises, including stretching. The device includes a foot loop, a hand grip, and an adjustable strap linking the foot loop to the harness. The device only allows for stretching a single leg at a time.
These devices tend to be complicated by the number of straps and/or they lack portability. In addition, the devices are designed solely for stretching and do not address other muscle issues, such as soreness, that can be resolved by massaging. The present invention overcomes these limitations and shortcomings of the prior art with the rear chain stretcher as described in detail below.